pneumatic tires

Abstract

To provide a pneumatic tire capable of reducing an uneven shape generated in a tire inner surface in a buttress region provided with a raised portion.SOLUTION: A pneumatic tire includes: a carcass extending in a toroidal shape straddling between a pair of bead parts; an inner liner arranged in a tire inner surface along the carcass; a belt layer laminated on the outside in the tire radial direction of the carcass; a plurality of raised parts disposed in at least one of buttress regions of a pair of side walls and aligned along the tire circumferential direction; and a rubber sheet arranged in a region including a range from a position of 34% of a tire cross section height from a tire outermost diameter position to a tire radial direction inner side to a position where a linear line extending in the tire radial direction passing an edge part of the belt layer crosses the inner liner, and interposed between the carcass and the inner liner.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] SUMMARY The present disclosure relates to pneumatic tires having raised portions in the buttress areas of the sidewalls. [Background technology]

[0002] Pneumatic tires are known that have raised portions in the buttress region that protrude from the profile line of the sidewall in order to improve driving performance on rough roads such as muddy, rocky, and snowy roads. In such tires, the outer surface of the buttress region has an uneven shape formed by multiple raised portions aligned along the tire circumferential direction. This provides a traction effect due to shear resistance when driving on rough roads, improving off-road performance.

[0003] FIG. 5 is a schematic diagram showing the outer surface of the buttress region. An outer surface 90 has an uneven shape formed by a plurality of raised portions 91 arranged in the tire circumferential direction (left-right direction in FIG. 5). As an indicator of the gentleness / abruptness of the uneven shape, a zigzag line ZL is drawn connecting the center of the top surface of the raised portion 91 and the center of the portion where no raised portion 91 is provided. In example (B), the arrangement pitch of the raised portions 91 is smaller than in example (A), resulting in a greater gradient of the zigzag line ZL. Thus, even if the raised height of the raised portions 91 is the same, the uneven shape can become more abrupt depending on the arrangement pitch.

[0004] The inventors have found through their research that when a tire with raised portions in the buttress region is vulcanized and molded, the unevenness of the outer surface of the buttress region can also cause unevenness on the inner surface of the tire, and that the more abrupt the unevenness of the outer surface, the more pronounced this unevenness becomes. Although the unevenness that occurs on the inner surface of the tire is gentler than the unevenness of the outer surface, if it becomes a little too abrupt, the inner liner may be damaged by the carcass cords, reducing air permeation resistance, and so it is desirable to alleviate this.

[0005] Patent Document 1 discloses a pneumatic tire with raised portions in the buttress region. In this tire, a reinforcing rubber layer is disposed in the buttress region between the carcass and the inner liner to suppress deformation of the buttress region during rolling. However, because this reinforcing rubber layer contains short fibers oriented in a specific direction, if an uneven shape occurs on the inner surface of the tire, the short fibers may damage the inner liner, which is thought to worsen the condition. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-177065 Summary of the Invention [Problem to be solved by the invention]

[0007] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a pneumatic tire that can reduce uneven shapes that occur on the inner surface of the tire in the buttress region where raised portions are provided. [Means for solving the problem]

[0008] The pneumatic tire of the present disclosure includes: a pair of bead portions; a pair of sidewalls extending radially outward from each of the pair of bead portions; a tread connected to each of the pair of sidewalls at an outer end in the tire radial direction; a carcass extending in a toroidal shape across the pair of bead portions; an inner liner disposed on the tire inner surface along the carcass; a belt layer laminated on the outer side of the carcass in the tire radial direction; a plurality of raised portions provided in a buttress region of at least one of the pair of sidewalls and arranged along the tire circumferential direction; The tire is provided with a rubber sheet that is disposed in an area including a range from a position that is 34% of the tire cross-sectional height radially inward from the outermost diameter position of the tire to a position where a straight line extending in the tire radial direction through the edge portion of the belt layer intersects with the inner liner, and is interposed between the carcass and the inner liner. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a meridian cross-sectional view of a tire that schematically illustrates an example of a pneumatic tire according to the present disclosure. [Figure 2] FIG. 2 is an enlarged cross-sectional view showing a main part of the pneumatic tire of FIG. 1. [Figure 3] Tire plan view showing the buttress area [Figure 4] FIG. 3 is an enlarged cross-sectional view showing a main part of FIG. 2. [Figure 5] Schematic diagram showing the outer surface of the buttress region DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a pneumatic tire according to the present disclosure will be described with reference to the drawings.

[0011] 1 and 2 is a pneumatic radial tire designed for running on rough roads including muddy and rocky terrain. The pneumatic tire T includes a pair of bead portions 1, a pair of sidewalls 2 extending radially outward from each of the pair of bead portions 1, a tread 3 continuing to the radially outer ends of each of the pair of sidewalls 2, a carcass 4 extending in a toroidal shape across the pair of bead portions 1, and an inner liner 14 disposed on the inner surface of the tire along the carcass 4. The inner liner 14 is formed from a rubber composition that has excellent air permeability (air permeability resistance).

[0012] Here, the tire radial direction is the direction along the diameter of the tire T, and corresponds to the up-down direction in the drawings. In Figures 1 and 2, the upper side is the outer side in the tire radial direction, and the lower side is the inner side in the tire radial direction. The tire width direction is the direction parallel to the rotation axis of the tire T, and corresponds to the left-right direction in the drawings. The side closer to the tire equatorial plane TC (left side in Figure 2) is the inner side in the tire width direction, and the side away from the tire equatorial plane TC (right side in Figure 2) is the outer side in the tire width direction. The tire circumferential direction is the direction around the rotation axis of the tire T.

[0013] An annular bead core 1a and a bead filler 1b are embedded in the bead portion 1. The bead core 1a is formed by covering a bundle of steel wires or the like with rubber. The bead filler 1b is disposed radially outward of the bead core 1a. The bead filler 1b is formed of rubber with a triangular cross section that extends radially outward from the bead core 1a. A rim strip rubber 11 that forms the outer surface of the bead portion 1 is provided radially outward of the rim strip rubber 11. A sidewall rubber 12 that forms the outer surface of the sidewall 2 is provided radially outward of the rim strip rubber 11.

[0014] The carcass 4 is disposed so as to span between the pair of bead cores 1a, and is wound up (i.e., turned up) from the inside to the outside in the tire width direction so as to sandwich the bead cores 1a and the bead fillers 1b. In other words, the carcass 4 has a main body portion extending from the tread 3 through the sidewalls 2 to the bead portions 1, and is provided with a continuous wound-up portion disposed on the outside of the bead cores 1a and the bead fillers 1b in the tire width direction.

[0015] The carcass 4 has two carcass plies 41, 42 laminated on top of each other. More specifically, the carcass 4 has the carcass ply 41 laminated relatively radially inward in the tread 3, and the carcass ply 42 laminated relatively radially outward in the tread 3. The carcass 4 is not limited to such a multi-layer structure formed by laminating a plurality of carcass plies, but may have a single-layer structure formed by one carcass ply. The number of carcass plies may be three or more.

[0016] The carcass ply 41 is formed by covering carcass cords (not shown) with topping rubber. The carcass cords are preferably made of metal such as steel or organic fibers such as polyester, rayon, nylon, or aramid. The carcass cords are arranged in a direction substantially perpendicular to the tire circumferential direction (for example, at an angle of 75 to 90 degrees relative to the tire circumferential direction). The carcass ply 42 has a structure similar to that of the carcass ply 41.

[0017] In this specification, of the turnup ends 41e, 42e of the multiple carcass plies 41, 42 of the carcass 4, the turnup end 41e located most outward in the tire radial direction is referred to as the turnup end 4e of the carcass 4. The turnup end 4e of the carcass 4 (i.e., the turnup end 41e) is located further outward in the tire radial direction than the tire maximum width position 2M, but is not limited to this. The turnup end 42e may also be located further outward in the tire radial direction than the turnup end 41e, in which case the turnup end 42e corresponds to the turnup end 4e of the carcass 4. The tire maximum width position 2M is the position at which the profile line 2p of the sidewall 2 in the tire meridian cross section is farthest from the tire equatorial plane TC in the tire width direction.

[0018] The pneumatic tire T also includes a belt layer 5 laminated on the tire radially outer side of the carcass 4. The belt layer 5 has a plurality of belt plies laminated on top of each other. The belt ply is formed by covering belt cords (not shown) with topping rubber. Steel is preferably used as the material for the belt cords. The belt cords are arranged in a direction inclined at a predetermined angle (for example, 20 to 30 degrees) with respect to the tire circumferential direction. In this embodiment, the belt layer 5 has two belt plies 51, 52, and the belt cords are laminated between them so that they cross each other in opposite directions.

[0019] A belt reinforcing layer 6 is disposed on the tire radial outer side of the belt layer 5. The belt reinforcing layer 6 has one or more reinforcing plies. The reinforcing plies are formed by covering reinforcing cords (not shown) with topping rubber. The reinforcing cords are preferably made of the organic fibers described above. The reinforcing cords are arranged along the tire circumferential direction. A tread rubber 13 that forms the outer surface of the tread 3 is disposed on the tire radial outer side of the belt reinforcing layer 6. Although not shown, the tread rubber 13 has various grooves such as circumferential grooves and lug grooves that form a tread pattern.

[0020] The pneumatic tire T of this embodiment is not a so-called side support type run-flat tire, and does not have a side reinforcing rubber layer with a crescent-shaped cross section provided on the sidewall 2. However, the tire is not limited to this, and may be a side support type run-flat tire in which a side reinforcing rubber layer is provided on the sidewall 2.

[0021] The pneumatic tire T also has a plurality of raised portions 7 arranged in the tire circumferential direction, as shown in Fig. 3, in a buttress region 2B of at least one of the pair of sidewalls 2. The buttress region 2B is a region on the outer side in the tire radial direction of the sidewall 2, more specifically, a region on the outer side in the tire radial direction of the tire than the tire's maximum width position 2M, and is a portion that does not come into contact with the ground during normal driving on flat, paved roads. On soft roads such as snowy roads or muddy ground, the tire sinks due to the weight of the vehicle, allowing the buttress region 2B to virtually come into contact with the ground, thereby obtaining a traction effect due to the shear resistance of the raised portions 7.

[0022] The raised portion 7 protrudes from the profile line 2p of the sidewall 2. The profile line 2p is the outline of the sidewall 2 excluding protrusions such as rim protectors. In Figures 1 and 2, part of the profile line 2p is shown by a dashed line. The profile line 2p is formed by a series of arcs that are smoothly connected together and have different radii of curvature. The profile line 2p may be formed by a single arc, or the radius of curvature may change continuously, or it may include a portion of a straight line. The outer surface of the buttress region 2B has an uneven shape formed by multiple raised portions 7 aligned along the tire circumferential direction.

[0023] The raised portion 7 extends along the tire radial direction. The tire radial distance D1 from the tire outermost diameter position Pm to the tire radially outer end 71 of the raised portion 7 is, for example, 10±5% of the tire cross-sectional height TH (see FIG. 1). The tire radial distance D2 from the tire outermost diameter position Pm to the tire radially inner end 72 of the raised portion 7 is, for example, 20 to 50% of the tire cross-sectional height TH. The maximum raised height of the raised portion 7 relative to the profile line 2p is, for example, 4 mm.

[0024] Figure 3 is a tire plan view showing the buttress region 2B. In Figure 3, the upper side is the inner side in the tire width direction, and the lower side is the outer side in the tire width direction. The left-right direction in Figure 3 corresponds to the tire circumferential direction. The outer side (shoulder portion) in the tire width direction of the tread 3 is provided with a plurality of lug grooves 31 extending in a direction intersecting the tire circumferential direction, and shoulder blocks 32 defined by the lug grooves 31. In this example, a so-called staggered shoulder is adopted, in which shoulder blocks 32a having edges positioned relatively outboard in the tire width direction and shoulder blocks 32b having edges positioned relatively inboard in the tire width direction are arranged alternately in the tire circumferential direction.

[0025] The raised portions 7 are provided at positions corresponding to the shoulder blocks 32. In the area shown in FIG. 3, four raised portions 7 are provided corresponding to the four shoulder blocks 32, respectively. Furthermore, raised portions 7a provided corresponding to shoulder block 32a and raised portions 7b provided corresponding to shoulder block 32b are paired and connected in the tire circumferential direction. Therefore, in the buttress region 2B, of the multiple lug grooves 31, lug groove 31a is closed by raised portions 7a and 7b, while lug groove 31b is not closed and is open radially inward. The shape of the raised portions 7 is not particularly limited.

[0026] In this embodiment, an example is shown in which 66 or more raised portions 7 are provided around the circumference. With this configuration, it is easy to obtain a traction effect due to shear resistance, especially when traveling on snowy roads. However, providing such a large number of raised portions 7 reduces the pitch at which the raised portions 7 are arranged, which can lead to a more abrupt uneven shape on the outer surface of the buttress region 2B (see FIG. 5). As a result, the phenomenon of unevenness occurring on the inner surface of the tire becomes more pronounced, making the provision of a rubber sheet 8, as described below, particularly useful. However, the number of raised portions 7 in a tire of the present disclosure is not limited to this.

[0027] The buttress region 2B is provided with an annular rib 17 that extends annularly in the tire circumferential direction across the raised portion 7. Like the raised portion 7, the annular rib 17 protrudes from the profile line 2p of the sidewall 2. The top surface of the annular rib 17 is set at the mold parting position, which is the boundary between the mold that forms the tread 3 and the mold that forms the sidewall 2, so a parting line may be formed on its outer surface. In a tire meridian cross section, the annular rib 17 has a stratovolcano shape with gently curved, constricted slopes. However, this is not limited to this, and other shapes such as a rectangular, trapezoidal, or triangular shape may also be used.

[0028] The pneumatic tire T also includes a rubber sheet 8 disposed in a region including a range R1 from position P1 to position P2 and interposed between the carcass 4 and the inner liner 14. Position P1 is a position 34% of the tire cross-sectional height TH radially inward from the tire's outermost diameter position Pm. Generally, the raised portion 7 tends to have a larger raised height radially outward from position P1. A radially inner end 82 of the rubber sheet 8 is disposed at this position P1 or further inward in the tire radial direction. Position P2 is a position where a straight line SL extending in the tire radial direction and passing through an edge portion of the belt layer 5 intersects with the inner liner 14. A radially outer end 81 of the rubber sheet 8 is disposed at this position P2 or further outward in the tire radial direction. By disposing the rubber sheet 8 in this region, it is possible to reduce the uneven shape generated on the tire inner surface in the buttress region 2B, thereby preventing damage to the inner liner 14 and suppressing a decrease in air permeability resistance.

[0029] According to research by the present inventors, the phenomenon in which the carcass cords press against the inner liner 14 due to the uneven shape of the tire inner surface is particularly noticeable within the range R1. Therefore, in this tire T, the rubber sheet 8 is arranged in a region including the range R1. The edge portion of the belt layer 5 through which the imaginary straight line SL passes is the outer edge portion in the tire width direction of the relatively wide belt ply 51 of the belt plies 51, 52 constituting the belt layer 5. In this embodiment, the edge portion of the belt layer 5 is located at approximately the same position in the tire width direction as the tread edge TE, or further outward in the tire width direction. The rubber sheet 8 is preferably arranged in a region overlapping 50% or more with the projected area of ​​the raised portion 7 toward the inner side in the tire width direction.

[0030] Like other rubber components constituting a tire, the rubber sheet 8 uses a rubber composition containing reinforcing fillers such as carbon black and silica. However, the rubber sheet 8 is formed from a rubber composition that does not contain reinforcing fibers. That is, the rubber sheet 8 is made of a rubber composition that does not contain reinforcing fibers made of long or short fibers such as metal fibers, organic fibers, glass fibers, or ceramic fibers. This is because if a rubber sheet containing such reinforcing fibers were used, the reinforcing fibers would press against the inner liner 14 due to the uneven shape of the tire inner surface, potentially worsening the condition.

[0031] In this embodiment, a TOS structure is adopted in which the tread rubber 13 is layered on the outside of the sidewall rubber 12. An outer end 12e of the sidewall rubber 12 in the tire radial direction is disposed between the belt layer 5 and the carcass 4. An outer end 81 of the rubber sheet 8 in the tire radial direction is disposed more inward in the tire width direction than the outer end 12e of the sidewall rubber 12 in the tire radial direction. In addition, the outer end 81 of the rubber sheet 8 is disposed more outward in the tire radial direction than the outer end 12e of the sidewall rubber 12 in the tire radial direction. The outer end 12e of the sidewall rubber 12 in the tire radial direction is sandwiched between a cushion rubber 9 and the carcass 4, which will be described later.

[0032] The pneumatic tire T includes a cushion rubber 9 disposed between the edge portion of the belt layer 5 and the carcass 4. This configuration increases the ground contact pressure in the shoulder portion of the tread 3, promoting uniform ground contact pressure distribution and suppressing uneven wear. The tire radially outer end 81 of the rubber sheet 8 is disposed outward in the tire width direction from the tire widthwise inner end 9e of the cushion rubber 9. This is because extending the rubber sheet 8 inward in the tire width direction beyond the cushion rubber 9 would not be expected to improve the tire's performance, and instead would be likely to result in adverse effects such as increased weight. The tire widthwise inner end 81 is disposed, for example, at a position 85±10% of the tread half width TW (see FIG. 1) outward in the tire width direction from the tire equatorial plane TC.

[0033] It is preferable that the tire radially inner end 82 of the rubber sheet 8 is disposed radially outward of the turned-up end 4e of the carcass 4 (turned-up end 41e in this embodiment). If not, a step will be large at the portion where the turned-up portion of the carcass 4 and the rubber sheet 8 overlap in the tire width direction, reducing the effect of reducing the uneven shape of the tire inner surface. The turned-up end 4e is disposed, for example, at a position 40±20% of the tire cross-sectional height TH radially inward of the tire's outermost diameter position Pm. In this embodiment, the tire radially inner end 82 is disposed radially outward of the tire's maximum width position 2M. Furthermore, the tire radially inner end 82 is disposed radially outward of the tire radially inner end 72 of the raised portion 7.

[0034] From the viewpoint of suppressing wear of the carcass cords against the inner liner 14 and reducing unevenness on the tire inner surface, the rubber hardness of the rubber sheet 8 is preferably greater than that of the topping rubber of the carcass 4. From the same viewpoint, the rubber hardness of the rubber sheet 8 is preferably greater than that of the inner liner 14. The rubber hardness of the rubber sheet 8 is preferably greater than that of the sidewall rubber 12. The rubber hardness of the rubber sheet 8 is preferably 3 or more times greater than the rubber hardness of each of the topping rubber of the carcass 4, the inner liner 14, and the sidewall rubber 12. The rubber hardness is measured in an atmosphere of 23°C using a Type A durometer hardness test in accordance with JIS K6253-1-2021.

[0035] From the viewpoint of reducing unevenness on the tire inner surface, the modulus (M100) of the rubber sheet 8 at 100% elongation is preferably larger than the M100 of the topping rubber of the carcass 4. From the same viewpoint, the M100 of the rubber sheet 8 is preferably larger than the M100 of the inner liner 14. The M100 of the rubber sheet 8 is preferably larger than the M100 of the sidewall rubber 12. The M100 of the rubber sheet 8 is preferably 0.5 MPa or more larger than the M100 of each of the topping rubber of the carcass 4, the inner liner 14, and the sidewall rubber 12. M100 is determined as the tensile stress at 100% elongation by a tensile test (using a No. 3 dumbbell) at 23°C in accordance with JIS K6251.

[0036] From the viewpoint of reducing unevenness on the tire inner surface, the modulus (M300) of the rubber sheet 8 at 300% elongation is preferably larger than the M300 of the inner liner 14. From the same viewpoint, the M300 of the rubber sheet 8 is preferably larger than the M300 of the sidewall rubber 12. The M300 of the rubber sheet 8 is preferably 3.0 MPa or more larger than the M300 of each of the inner liner 14 and the sidewall rubber 12. M300 is determined as the tensile stress at 300% elongation by a tensile test (using a No. 3 dumbbell) at 23°C in accordance with JIS K6251.

[0037] FIG. 4 shows the thicknesses of the rubber sheet 8, the inner liner 14, and the carcass ply 41. The thickness T8 of the rubber sheet 8 is preferably smaller than the thickness T14 of the inner liner 14. By using a rubber sheet 8 with a small thickness, it is possible to prevent unevenness caused by the rubber sheet 8 from occurring on the inner surface of the tire. For the same reason, the thickness T8 is preferably smaller than the thickness of the carcass ply. The thickness of the carcass ply is the thickness of one of the multiple carcass plies stacked together, for example, the thickness T41 of the carcass ply 41.

[0038] The thickness T8 of the rubber sheet 8 is assumed to be constant, but if it varies, the maximum thickness is taken as the thickness T8. The thickness T14 of the inner liner 14 and the thickness T41 of the carcass ply 41 are each measured at the same location as the thickness T8. The thickness T8 is, for example, 0.3 to 0.6 mm. The thickness T14 is, for example, 1.1 mm or more. The thickness T41 is, for example, 0.8 to 1.0 mm. In this case, the carcass ply 41 is formed, for example, by covering a carcass cord having a wire diameter of 0.50 to 0.70 mm with a topping rubber having a thickness of 0.15 mm. The carcass ply 42 has the same thickness as the carcass ply 41.

[0039] The buttress region 2B where the raised portion 7 and rubber sheet 8 are provided as described above may be the buttress region 2B of at least one of the pair of sidewalls 2. However, to enhance the improvement effect, it is preferable that they be provided in both of the pair of sidewalls 2. In this embodiment, the configuration of the raised portion 7 and rubber sheet 8 shown in Figure 2 is also applied to the sidewall 2 on the left side of Figure 1.

[0040] Unless otherwise specified, the shapes and dimensions described in this specification are based on a tire mounted on a standard rim, inflated to the standard internal pressure, and in a normal, unloaded state. A standard rim is a rim specified for each tire by the standard system, including the standard on which the tire is based, such as a "standard rim" in JATMA, a "design rim" in TRA, or a "measuring rim" in ETRTO. The standard internal pressure is the air pressure specified for each tire by the standard system, including the standard on which the tire is based, such as the "maximum air pressure" in JATMA, the maximum value listed in the "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURE" table in TRA, or the "INFLATION PRESSURE" in ETRTO.

[0041] As described above, the pneumatic tire T of this embodiment includes a pair of bead portions 1, a pair of sidewalls 2 extending radially outward from each of the pair of bead portions 1, a tread 3 connected to the radially outer ends of each of the pair of sidewalls 2, a carcass 4 extending toroidally across between the pair of bead portions 1, an inner liner 14 disposed on the inner surface of the tire along the carcass 4, a belt layer 5 laminated on the radially outer side of the carcass 4, a plurality of raised portions 7 provided in the buttress region 2B of at least one of the pair of sidewalls 2 and aligned along the tire circumferential direction, and a rubber sheet 8 interposed between the carcass 4 and the inner liner 14, and disposed in a region including a range R1 from a position P1 that is 34% of the tire cross-sectional height TH radially inward from the tire outermost diameter position Pm to a position P2 at which a straight line SL that extends radially inward in the tire and passes through an edge portion of the belt layer 5 intersects with the inner liner 14. According to this configuration, the rubber sheet 8 interposed between the carcass 4 and the inner liner 14 can reduce the uneven shape that occurs on the inner surface of the tire in the buttress region 2B, which in turn prevents damage to the inner liner 14 and suppresses a decrease in air permeability resistance.

[0042] It is preferable that the tire radially outer end 12e of the sidewall rubber 12 forming the outer surface of the sidewall 2 is disposed between the belt layer 5 and the carcass 4, and the tire radially outer end 81 of the rubber sheet 8 is disposed more inward in the tire width direction than the tire radially outer end 12e of the sidewall rubber 12. This allows the rubber sheet 8 to be appropriately disposed in a region that is preferable for reducing uneven shapes that occur on the tire inner surface.

[0043] It is preferable that the outer end 81 in the tire radial direction of the rubber sheet 8 is disposed more outer in the tire width direction than the inner end 9e in the tire width direction of the cushion rubber 9 disposed between the edge portion of the belt layer 5 and the carcass 4. By not extending the rubber sheet 8 more than necessary, adverse effects such as an increase in weight can be suppressed.

[0044] The rubber hardness of the rubber sheet 8 is preferably greater than the rubber hardness of the topping rubber of the carcass 4. This configuration can suppress wear of the carcass cords against the inner liner 14, effectively reducing unevenness on the inner surface of the tire.

[0045] The thickness T8 of the rubber sheet 8 is preferably smaller than the thicknesses of the inner liner 14 and the carcass ply 41. By using a rubber sheet 8 with such a small thickness, it is possible to prevent unevenness caused by the rubber sheet 8 from occurring on the inner surface of the tire.

[0046] The pneumatic tire of the present disclosure can be used as various tires for passenger cars, light trucks, trucks, buses, etc.

[0047] The pneumatic tire of the present disclosure is not limited to the above-described embodiment, and various improvements and modifications are possible within the scope of the spirit thereof. [Explanation of symbols]

[0048] 1 Bead section 2 Sidewall 2B Buttress area 3 Tread 4. Carcass 5 Belt Layer 7 Ridges 8 rubber sheets 9 Cushion Rubber 12 Sidewall rubber 14 Inner liner

Claims

1. a pair of bead portions; a pair of sidewalls extending radially outward from each of the pair of bead portions; a tread connected to each of the pair of sidewalls at an outer end in the tire radial direction; a carcass extending in a toroidal shape across the pair of bead portions; an inner liner disposed on the tire inner surface along the carcass; a belt layer laminated on the outer side of the carcass in the tire radial direction; a plurality of raised portions provided in a buttress region of at least one of the pair of sidewalls and arranged along the tire circumferential direction; a rubber sheet disposed in a region including a range from a position that is 34% of the tire cross-sectional height radially inward from the outermost radial position of the tire to a position where a straight line that passes through an edge portion of the belt layer and extends in the tire radial direction intersects with the inner liner, and is interposed between the carcass and the inner liner, The rubber sheet is a pneumatic tire formed from a rubber composition containing no reinforcing fibers.

2. an outer end in the tire radial direction of a sidewall rubber forming an outer surface of the sidewall is disposed between the belt layer and the carcass; The pneumatic tire according to claim 1 , wherein an outer end in the tire radial direction of the rubber sheet is disposed more inward in the tire width direction than an outer end in the tire radial direction of the sidewall rubber.

3. 3. The pneumatic tire according to claim 2, wherein an outer end in the tire radial direction of the rubber sheet is disposed outward in the tire width direction from an inner end in the tire width direction of a cushion rubber disposed between the edge portion of the belt layer and the carcass.

4. The pneumatic tire according to any one of claims 1 to 3, wherein the rubber sheet has a rubber hardness greater than a rubber hardness of the topping rubber of the carcass.

5. The pneumatic tire according to any one of claims 1 to 4, wherein the rubber sheet has a thickness smaller than that of the inner liner and the carcass ply.

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